They are planning on abandoning the BMI. BMI doesn't take into account if you are old (more fat, less heavy muscles). Doesn't take into account Bone density.
Some nutritionist at my school told me as people drink less milk the rate of obesity rose over the years (didn't ask what source she got this from). This doesn't show cause and effect, but maybe that extra calcium has a role in metabolism we don't know about yet. SKIM milk, anyone? I guess if you are just drinking water and but eating a lot of other nutrient rich foods, then that should yield all the nutrients you need to produce enzymes for an active metabolism without the 999999999999 unnecessary calories you get in pop, or even in orange juice..